Non-volatile memory (NVM) circuits have achieved widespread adoptions for code and data storage applications. An important aspect of NVM circuits is their performance, which includes endurance (number of programming or write/erase cycles) and data retention after write/erase cycling. Within the industry, the performance of NVM technology has been characterized extensively. Generally, the NVM circuits should be able to endure over 100 thousand to 1 million programming cycles with data retention exceeding 20 years, even at extreme ambient temperatures.
Programming the memory to a program state involves, for example, injecting hot electrons into the gate dielectric of the floating or select gate of the memory cell, while erasing involves discharging the gate dielectric by (Fowler-Nordheim) FN tunneling. Leakage paths in the dielectric layer can exist, degrading the retention of the memory cell.